/Engine/Source/Runtime/RHI/Public/RHIContext.h
virtual void RHICopyBufferRegion ( [FRHIBuffer](API\Runtime\RHI\FRHIBuffer) * DestBuffer, uint64 DstOffset, [FRHIBuffer](API\Runtime\RHI\FRHIBuffer) * SourceBuffer, uint64 SrcOffset, uint64 NumBytes )